Device, assembly and method for testing electronic components, and calibrating method therefor

ABSTRACT

The invention relates to a test device for testing electronic components mounted on a carrier such as a lead frame, comprising: a transport path for supplying a carrier for testing; a manipulator for engaging and displacing a supplied carrier; a test contact with which a carrier and/or at least one component mounted on the carrier can be placed in contact by the manipulator; and a transport path for discharging a tested carrier. The invention also embraces a test assembly which includes at least one described test device. The invention furthermore provides a method for testing electronic components mounted on a carrier and method for calibrating a test device.

BACKGROUND OF THE INVENTION

The invention relates to a test device for testing electronic componentsmounted on a carrier such as a lead frame or substrate. The inventionalso relates to a test assembly of which at least one such test deviceforms part. In addition, the invention provides a method for testingelectronic components mounted on a carrier such as a lead frame and amethod for calibrating a test device.

The testing of electronic components, particularly semiconductors,usually takes place according to the prior art after a plurality ofelectronic components have been placed on a carrier. The carrier issubsequently subdivided into segments on which one component is situatedin each case. The separate carrier segments with electronic componentsmounted thereon are individually placed for testing against for instancea test contact with which the measurement is performed.

The present invention has for its object to provide an improved testdevice and method for testing electronic components with which testingcan take place in accurate manner at relatively high speed.

SUMMARY OF THE INVENTION

The invention provides for this purpose a test device. In a preferredembodiment the transport path for supplying a carrier connects onto thetransport path for discharging a carrier. In another preferredembodiment the transport path for supplying a carrier runs at leastpartly parallel to at least a part of the transport path for discharginga carrier. Using this test device a whole carrier with a plurality ofelectronic components mounted thereon can be engaged in one operation.The engaged carrier and/or the electronic components mounted thereon cannow be placed into contact, once or a number of times at differentpositions, with one or more test contacts. A significant advantage ofthe device according to the invention is that the time required fortesting an electronic component can be considerably reduced. Fewerseparate objects are carried into the test device. Another advantage ofthe test device according to the invention is that the accuracy ofpositioning of the component relative to the contacts increases so thatthe quality of contact improves and becomes more constant. The carrierdoes after all contain the original reference points (also designated asindex holes) on the basis of which previous operations have taken place.When the electronic components are separated for the test device, usemust be made for later positioning of derived reference points such asfor instance a moulded housing. It will be apparent that use of theoriginal reference points on the carrier enables a more precisepositioning of the objects for testing. The accuracy of the measurementwill hereby increase, whereby fewer products are unnecessarily rejectedas a result. Yet another advantage of the test device according to theinvention is that it enables testing relatively early in the productionprocess, so that relatively quicker feedback is possible when errors aredetected and whereby possibly expensive further operations can bedispensed with. Because a carrier for testing is taken from a supplypath and a tested carrier is placed in a discharge path, a plurality oftesting devices can be deployed parallel to each other for testing aproduction flow of carriers. The capacity of the testing device does nottherefore need to form a bottle-neck in a production process. The supplyand discharge of carriers can take place via a single transport path, inwhich case it is advisable to record which carriers have been tested andwhich have not been tested, but it is also possible to use differenttransport paths for supply and discharge of carriers. In this lattersituation there is less necessity for monitoring which carriers havebeen tested since the presence in the discharge path already indicatesthat a carrier has been tested. It is however possible in both variantsto deploy test devices parallel to each other.

In a preferred embodiment at least one transport path is adapted fortransport in two directions. The flexibility of the test device ishereby further increased, particularly in respect of the arrangement inwhich it is used.

The manipulator is preferably provided with two substantially mutuallyperpendicular linear guides for displacing the manipulator in a plane.The manipulator can herein also be provided with a third linear guidewhich lies substantially perpendicular to the other two linear guides.Such a manipulator enables a precise positioning of the carrier relativeto the test contact. It is also possible to use such a manipulator forplacing carrier and test contact into mutual contact a number of times,for instance at different locations on the carrier. A precisepositioning of carrier relative to test contact is then also possible.An advantage already described above is the short transporting timerequired between two measurement on the same carrier. Yet anotheradvantage of the manipulator with linear guiding is that it isrelatively inexpensive to manufacture and is easily maintained.

In yet another preferred embodiment, the test device is provided withidentification means for identification of an individual carrier. Thetest results of determined positions on the carrier can thus be linkedto the individual carrier so that in optional further processing of acarrier the test results can be taken into account.

In yet another preferred embodiment, the manipulator is provided withpositioning means for positioning the carrier relative to themanipulator. Using the positioning means the manipulator can bepositioned on the carrier relative to the original reference points.

For processing of the test data the test device preferably comprises acomputer system which is connected to the test contact. In practice sucha computer system is a number of times more expensive (for instance by afactor 4) than the test device itself. The productivity increase of thetest device according to the invention compared to the prior art alsoentails that the productivity of the relatively expensive computersystem also increases. Reduction of the processing time per measurementthus provides an advantage which extends beyond more optimal utilizationof the test device without peripheral equipment.

The invention also provides a test assembly for testing electroniccomponents mounted on a carrier such as a lead frame. Such a testassembly can operate as stand-alone unit but can also be built into aproduction line. In addition, one or more test devices can beincorporated in the test assembly as required.

The invention moreover provides a method for testing components mountedon a carrier such as a lead frame. A carrier can herein be tested duringstep C) by placing it in contact with a test contact. It is alsopossible for a carrier and/or components mounted on a carrier to betested a number of times by placing these in contact with the testcontact at a plurality of positions. It is also further possible to testthe carrier and/or components mounted on a carrier a number of times byplacing them in contact with a plurality of test contacts. This can takeplace simultaneously as well as successively. By taking a whole carrierwith electronic components mounted thereon out of a transport path theadvantages are obtained as already described above with reference to thedevice according to the invention. The relatively simple method enablesit to be performed with a relatively simple device. Measurements can beperformed at relatively high temperatures (100-200° C.) but it is alsopossible to perform the method at relatively low temperatures (−60-−20°C.). The device according to the invention can be used for cold as wellas hot test conditions.

Depending on the conditions in which the test is carried out, thecarrier can be taken before testing out of the same transport path as,or out of a different transport path from the one in which it is placedafter testing. In a stand-alone application of the method, a singletransport path may for instance suffice but in a situation where themethod is performed simultaneously at different positions a multipletransport path is preferred.

The present invention will be further elucidated with reference to thenon-limitative embodiments shown in the following figures. Herein:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic perspective view of a device according to theinvention,

FIG. 2 shows a schematic perspective view of a variant of the deviceshown in FIG. 1, and

FIG. 3 shows a schematic view of a part of the device as shown in FIGS.1 and 2 which is coupled to a computer.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a test device 1 with a feed conveyor 2 along which a leadframe 3 for testing is supplied. When lead frame 3 has reached adetermined position it will be engaged by a manipulator 6 which isprovided for this purpose with movable rippers 7. Manipulator 6 ismovably suspended by means of a frame 8. In this frame 8 is arranged avertical linear guide 9 (Z-axis) with which manipulator 6 isdisplaceable in vertical direction. Also arranged in frame 8 are twohorizontal linear guides 10, 11 which lie perpendicularly of oneanother. Manipulator 6 is movable by horizontal linear guides 10, 11 ina plane which lies at least partly above feed conveyor 2 for lead frame3 and a discharge conveyor 4 for discharge of tested lead frames 5.

After a lead frame 3 for testing has been taken from feed conveyor 2,manipulator 6 is moved to above a test contact 12. This test contact 12is provided with positioning pins 13 which co-act with index holes 25,which are arranged in lead frames 3 for testing. As an alternative it isalso possible to provide the manipilator 6 with positioning pins 13cooperating with recesses in the test contact 12. When manipulator 6 issituated with a lead frame 3 for testing above test contact 12,manipulator 6 will be moved downward by the vertical linear guide 9 suchthat positioning pins 13 engage in the index holes of lead frame 3. Whenmanipulator 6 is moved downward the lead frame 3, or an electroniccomponent mounted thereon, will make contact with the conducting stops14 arranged on test contact 12. The measurement can subsequently beperformed, and this will be further discussed with reference to FIG. 3;

After performing of the first measurement the manipulator 6 is moved alimited distance upward such that lead frame 3 is released frompositioning pins 13. Subject to the test programme to be run, lead frame3 can now be displaced through a limited distance in X or Y direction tothen be moved downward again so that a subsequent test can be carriedout with lead frame 3. A number of tests can thus be performed on asingle lead frame 3. Usually The number of tests to be carried out willusually correspond with the number of electronic components arranged onlead frame 3. Because in the case of successive measurements on the samelead frame 3 the relative displacements of lead frame 3 are relativelysmall, the processing time per test for performing is also limited. Inorder to perform a number of very diverse tests on the same lead frame 3for testing a plurality of test contacts 12 of diverse geometry can alsobe placed in the same test device 1.

After all required tests have been carried out, manipulator 6 isdisplaced to a position above discharge conveyor 4 on which a testedlead frame 5 is set down by opening grippers 7. Depending on thequantity of lead frames for testing and the complexity of the tests tobe performed, one or more test devices 1 can be combined. This combiningof a plurality of test devices 1 can be realized relatively simply whenfeed conveyor 2 and discharge conveyor 4 are separated. However, alsowhen only one combined feed and discharge conveyor is used it ispossible to combine a plurality of test devices 1. A control system mosthowever be used in this cast which monitors which lead frame 4 lying onthe conveyor has already been tested and which lead frame 3 has not yetbeen tested.

The test device 1 according to the invention has the advantage that veryfew product-dependent components form part of test device 1. Test device1 can hereby be changed over relatively quickly for processing ofdifferent types of product. The most product-dependent component in testdevice 1 is the test contact 12 which can be embodied for quickreplacement, for instance by means of rapid-action couplings.

FIG. 2 shows a test device 15 in which, in addition to the componentsshown in FIG. 1, two transfer devices 16, 17 are also arranged forremoving a lead frame 3 for testing from a transport track 26 andplacing a tested lead frame 5 after testing on the transport track 26. Alead frame 3 is displaced to an infeed station 18 above which isdisposed a camera 19. A first visual inspection of lead frame 3 can beperformed herewith. The camera 19 can also be equipped as a data codereader for reading a code marking a lead frame and identifying it. Basedon this information a link can be made relating a test result andindividual components on the lead frame 3. The information can be usedfor selectioning of the tested components later on. Manipulator 6engages lead frame 3 in infeed station 18 and moves it to test contact12 where the tests as described above are carried out. After the testshave been performed the tested lead frame 5 will be placed bymanipulator 6 in an outfeed station 20. In addition to camera 19 placedat the infeed station 18, it is also possible for other test equipmentto be deployed close to infeed station 18 and outfeed station 20.

The test device 15 is provided with a frame 27 for carrying themanipulator 6 that is less complete than the frame 8 showed in FIG. 1.The frame 27 creates freedom for the manipulator 6 in only twodirections, the X- and Z-axis. As freedom in the Y direction, as showedin test device 15 in FIG. 1, is superfluous because of the transferdevices 16, 17 the frame 27 can be relatively simple.

The transfer devices 16, 17 increase the capacity of test device 15 inthat manipulator 6 only has to displace a lead frame 3, 5 over a limiteddistance, since the operations by transfer devices 16, 17 andmanipulator 6 can take place in parallel manner, the productivity oftest device 15 is greater than that of test device 1. In addition,infeed and outfeed stations 18, 20 enable additional inspections.

FIG. 3 shows schematically a computer 22 as visualization of a so-calledtest system which in practice consists of a mainframe with relativelycomplex test software. An individual test system 22 is used per testdevice 1, 15. Test system 22 is connected by means of a signal line 23to the conducting stops 14 of test contact 12. Also shown schematicallyis a sensor 24 which is accommodated in manipulator 6 for identificationof an engaged lead frame 3. The test results of a lead frame 3 can thusbe linked to the identity of lead frame 3.

What is claimed is:
 1. A test device for testing electronic components,comprising: a lead frame on which a plurality of electronic componentsmay be mounted for testing wherein the lead frame is arranged with indexholes; a lead frame supply transport path; a manipulator for engagingand displacing a supplied lead frame; a test contact with which a leadframe and/or at least one component mounted on the lead frame can beplaced in contact by the manipulator wherein the test contact isprovided with positioning pins which co-act with the index holesarranged in the lead frame; a lead frame discharge transport path;wherein at least one of said transport paths is continuous and leadsalong the test contact; and wherein the manipulator for engaging anddisplacing a supplied lead frame is equipped for taking a lead framefrom the supply transport path and, after displacing and testing thelead frame, the manipulator places the tested lead frame in saiddischarge transport path.
 2. The test device as claimed in claim 1,wherein the transport path for supplying a lead frame is connected tothe transport path for discharging a lead frame.
 3. The test device asclaimed in claim 1, wherein the transport path for supplying a leadframe runs at least partly parallel to at least a part of the transportpath for discharging a lead frame.
 4. The test device as claimed inclaim 1, wherein at least one transport path is adapted for transport intwo directions.
 5. The test device as claimed in claim 1, wherein thetest device comprises identification means for identification of anindividual lead frame.
 6. The test device as claimed in claim 1, whereinthe test device also comprises a computer system for processing testdata, which computer system is connected to the test contact.